I followed a link in Wavepad and found this. It may be worth a try.
While it is said that 'The Meek Shall Inherit The Earth', nobody guaranteed what state it would be in when they got it!
Duble-click on the speaker icon in the system tray. Make sure the slider on microphone is near the top. If microphone doesn't show, click Options > Properties > Recording and put a tick in the box next to microphone.
Ok between you guys, you have sorted me out. The Record Pad and Wave Pad are great pieces of freeware, and the microphone boost is exactly what I needed.